The technical field of electronic imaging is evolving fast and there are a lot of different manufacturers producing components and systems for electronic imaging.
The imaging systems, and especially the image sensor, require intricate timing signals in order to operate. Further, the required signals varies in both function and appearance between different systems and between different implementations of specific components.
The timing signals are generated by means of a timing generator. Often the timing generators are implemented as complex state machines that are designed to provide timing signals to a specific imaging system implemented by means of a specific set of components. Thus, a new timing generator has to be manufactured for every new imaging system and every time a component in an existing imaging system is exchanged for another one of said component. To design and produce a new timing generator every time a signal has to be added or altered is time-consuming and expensive.
In order to overcome the above mentioned problem some more or less programmable timing generators have been developed.
In the international application WO 01/15436 A1 there is described a timing generator that generates waveforms based on a waveform control word stored in a single static random access memory (SRAM). Additionally, the timing generator includes a line control unit for generating a lower level waveform, a frame control unit and an arbitrator. The arbitrator controls the distribution of waveform control words to the line control unit and the frame control unit. The control of the arbitrator is based on signals provided from the line control unit and the frame control unit, respectively. Said signals being a signal from the frame control unit regarding an ended frame cycle and signals from the line control unit regarding an ended cycle or a reception of the next line type. Basically, the system generates a signal in accordance with a waveform control word including the level of each timing signal and a value indicating the number of cycles this word defines the levels of the timing signals. When the indicated number of cycles has been processed the waveform control word in the following address is passed to the control unit for defining the timing signals.
The timing generator above is more flexible than a prior art state machine. However, in some situations said timing generator may require a lot of memory and much effort may be required for setting the waveform control words.